1 Samuel 17:55-58

55Now when Saul saw David going out against the Philistine, he asked Abner, the commander of the army, “Abner, whose son is this boy?” Abner said, “As your soul lives, your majesty, I don’t know.”

56So the king said, “Then, find out whose son this young man is.”

57So when David returned from killing the Philistine, Abner took him and brought him before Saul with the head of the Philistine in his hand.

58“Whose son are you, young man?” Saul said to him. David answered, “I am the son of your servant Jesse the Beth-lehemite.”